The millimeter wave (mmW) frequencies provide a huge amount of spectrum. The 60 GHz unlicensed spectrum alone is about 7 GHz (depending on country) and there is potentially much more that may become available either as licensed, lightly licensed, or unlicensed spectrum.
In order to close the link budget for mmWs, highly directional antennas may be needed and may become practical (for example, wireless HD devices). There is a synergetic effect to be exploited at higher frequencies that is not possible below sub-6 GHz; namely, there is potential of much greater spatial reuse. The higher gain antennas that are needed for millimeter wave communications have the associated benefit of greater directionality which reduces the interference seen by unintended receivers.
At mmW frequencies, large carrier bandwidths are achievable with comparatively low fractional bandwidths. This enables single radio solutions capable of addressing large amount of spectrum. Utilizing mmW frequencies may also lead to lower power consumption because of high directional antennas and by trading bandwidth for power (Shannon's law).
However, there are many associated challenges. The mmW carriers have near optical properties with high penetration losses, high reflection losses, and little diffraction, leading to line of sight (LOS) dominated coverage. Millimeter wave frequencies are also subject to a host of propagation challenges (especially high oxygen absorption concern for 60 GHz band).